On Fri, Jan 14, 2011 at 5:15 AM, Alex Boyko <alex.kyr...@gmail.com> wrote:
> So, I'd like to know how should I implement (if it's possible of course)
> __iter__ for my tree class based on recursion without generators?
You could try something like this (untested):
from itertools import chain, imap
...
def postorder(self, node):
return chain(chain.from_iterable(imap(self.postorder,
node.childs)), [node])
Or you could write the iterator the old-fashioned way, as an object
with state (also untested):
def __iter__(self):
return PostOrderIter(self.root)
class PostOrderIter(object):
def __iter__(self, node):
self.stack = [(node, 0)]
def next(self):
if not self.stack:
raise StopIteration
node, index = self.stack.pop()
if index < len(node.childs):
child = node.childs[index]
self.stack.append((node, index+1))
self.stack.append((child, 0))
return self.next()
else:
return node
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